1. Field of the Invention
The present invention relates to a fuel injection apparatus for internal combustion engines, and more particularly to a fuel injection apparatus in which maximum fuel injection can be adjusted in accordance with the fuel injection advance.
2. Description of the Prior Art
The control of the amount of fuel injection, especially the control of the maximum amount of fuel injection, of the conventional fuel injection apparatus for internal combustion engines is generally determined on the basis of the rotational speed of the internal combustion engine. However, in Japanese Utility Model Public Disclosure No. 136138/81, there is proposed an apparatus in which the maximum amount of fuel injection is controlled depending upon whether or not the apparatus is in the state that free-acceleration is possible. On the other hand, in controlling the timing of fuel injection, not only the rotational speed of the engine, but also the acceleration of the engine, the coolant temperature, the engine load and the like are generally taken into consideration (i.e., Japanese Patent Publication No. 39285/76).
The control of fuel injection timing in the conventional fuel injection apparatus has a large effect on the torque of the internal combustion engine. More specifically, when the timing of fuel injection varies within a predetermined adjustment range, even if the engine speed and the amount of fuel injection are not changed, the engine torque increases with the advance of fuel injection timing and decreases with increasing lag of the injection timing. Therefore, a fuel injection apparatus constituted by a combination of the prior art apparatuses described above has a disadvantage in that the maximum engine torque varies depending upon the fuel injection timing even when the engine speed is maintained constant, so that the operator experiences a feeling of discomfort.